CaF2 powder was prepared by aqueous solutions direct precipitation methods,with Ca(NO3)2 and KF as raw materials.Through XRD,SEM,particle size analysis methods,the influences of reactant concentration on CaF2 powder grain size,particle size and distribution were studied,which provide an experimental basis for the simple preparation of large number of CaF2 nanopowders.The results show that: With the increase in the concentration of reactants,the grain size of CaF2 powders increase first and then decreases,powder particle size decreases with the grain size decreases,and the subsequent narrowing the scope of particle size distribution.When the reactant concentration reach saturation concentration,the grain size of the prepared CaF2 powder is minimum,the powder shows a little reunion,and its particle size distribution is of mono-dispersed.